EMB135 SUFFERS LOSS OF BLEED AIR FOR DEICING SHORTLY AFTER TKOF ENRTE TO DEST WITH POTENTIAL ICING CONDITIONS. DISPATCH AND MAINT SAY TO CONTINUE. FLT CREW DETERMINES TO RETURN TO DEP STATION INSTEAD.

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ON CLBOUT FROM CMH; WE ENCOUNTERED ICING AT APPROX 3000 FT MSL AND ALMOST IMMEDIATELY RECEIVED A BLEED 1 OVERTEMP EICAS MESSAGE. WHEN WE RAN THE QRH AND SHUT OFF BLEED 1 AS REQUIRED; THE OVERTEMP MESSAGE WENT AWAY. WE REACHED DISPATCH AND MAINT CTL TO MAKE THE GO/RETURN DECISION. DISPATCH AND MAINT CTL CONFERRED AND SAID WE WOULD BE OK TO CONTINUE TO BOS GIVEN THE WX FORECAST. THEY TOLD US TO EXPECT CONTRACT MAINT ON THE GND IN BOS FOR A BLEED SYS 1 DEFERRAL. WE ASKED IF IT WOULD BE SAFE TO CONTINUE TO BOS; GIVEN THE WX WAS IMC AND HAD SNOW IN THE FORECAST; BUT DISPATCH AND MAINT CTL SAID WE COULD CONTINUE AND DEAL WITH THE PROB ON THE GND IN BOS. AT THIS POINT; WE WERE TOO BUSY TO VERIFY THE MEL ITEMS FOR SINGLE BLEED OP. THE DISPATCHER SAID THERE WAS NO ICING FORECAST IN EITHER BOS OR CMH AND; THEREFORE; THE FLT WOULD BE FINE ACCORDING TO MAINT CTL. DISPATCH GAVE US FUEL BURN NUMBERS FOR THE CONTINUED FLT AT FL250. WE WERE IN LEVEL FLT AT 10000 FT ABOVE 50 MI OR LESS FROM CMH AT MINIMUM AIRSPD IN VMC WHEN THE DECISION WAS MADE TO CONTINUE. AFTER MY CONVERSATION WITH DISPATCH; THE FO AND I REVIEWED THE CHKLISTS ASSOCIATED WITH SINGLE-BLEED OP IN POSSIBLE ICING CONDITIONS. THERE ARE SEVERAL CHKLISTS FOR ANTI-ICING FAILURES DUE TO LOW BLEED CAPACITY WITH THE SINGLE-BLEED OPERATING. WE DISCOVERED THAT WITH 1 ENG BLEED SOURCE DEFERRED; WE WERE NOT PERMITTED TO FLY INTO KNOWN ICING CONDITIONS ACCORDING TO THE MEL. WE REVIEWED THE WX PACKET AND FOUND THAT THERE WERE FORECAST LOW CEILINGS AND POSSIBLE PRECIP THROUGH MOST OF THE NE WITH TEMPS AROUND FREEZING AT THE GND FOR ALL RPTING STATIONS. TO THE BEST OF OUR KNOWLEDGE; THERE WAS NO PLACE WITHIN OUR FUEL RANGE THAT WOULD PERMIT US TO LAND WITHOUT FLYING INTO KNOWN OR FORECAST ICING. IT ALSO OCCURRED TO US THAT WHEREVER WE LANDED WE WOULD NOT ONLY FACE POSSIBLE EMER ANTI-ICING FAILURES; BUT WOULD ADDITIONALLY BE STUCK AWAITING MAINT DUE TO THE 'NO FLT INTO KNOWN ICING' CAVEAT IN THE MEL. AFTER LEARNING THIS NEW INFO; WE CALLED DISPATCH BACK FOR AN ALTERNATE PLAN. WE DECIDED TO RETURN TO CMH WHERE WE KNEW THEY HAD VERY THIN CEILINGS AND; EVEN THOUGH WE WOULD BE FLYING THROUGH ICING TO LAND; WE HAD A KNOWN QUANTITY TO DEAL WITH RATHER THAN FLY INTO A RAIN AND SNOWSTORM FARTHER N. ON APCH TO CMH WE DID RECEIVE A WING ANTI-ICE FAIL MESSAGE AND HAD TO CONFIGURE THE AIRPLANE FOR LNDG EARLIER THAN NORMAL TO ENSURE ENG PWR AND BLEED AIR VOLUME WOULD BE SUFFICIENT FOR ANTI-ICING. WE WERE IN TRACE-TO-LIGHT ICING FOR LESS THAN 2 MINS BEFORE BREAKING OUT OF THE CLOUDS ON FINAL AND COULD SEE NO RESIDUAL ICE ON VISIBLE SURFACES. THE TOTAL FLT TIME WAS ABOUT 2 HRS FROM START TO FINISH; AND THEN ONLY THAT LONG BECAUSE IT TOOK THE FO AND I SO LONG TO GET THROUGH NORMAL FLT DUTIES AND THEN REVIEW THE OTHER APPLICABLE SYS AND MEL INFO. WE FLEW THROUGH ICING CONDITIONS SINGLE-BLEED INTO CMH BECAUSE; ACCORDING TO OUR BEST INFO; THERE WAS NO PLACE ELSE WE COULD GO AND LAND WITHOUT ENCOUNTERING CLOUDS AND CMH WAS THE BEST OVERALL OPTION. THIS FLT HAD SEVERAL ISSUES. THE FIRST ISSUE WAS MISCOM BTWN ME AND DISPATCH. WHEN WE CALLED; I INFORMED DISPATCH THAT ON DEP FROM CMH WE HAD RECEIVED THE BLEED OVERTEMP; AND WE WERE INFLT TRYING TO MAKE A CONTINUE OR RETURN DECISION. DISPATCH DID NOT CORRECTLY UNDERSTAND WHAT I TOLD THEM AND TOLD ME IN A LATER CONVERSATION THEY HAD ASSUMED WE WERE ON THE GND IN CMH AT THE TIME OF THE CALL RATHER THAN 50 MI N OF CMH AT 10000 FT. ANOTHER ISSUE IS THAT DISPATCH TOLD US WE COULD CONTINUE TO BOS BECAUSE; AS THE DISPATCHER SAID; THERE WAS NO FORECAST ICING BTWN BOS AND CMH. ACCORDING TO OUR WX RPTS IN HAND; ALL FIELDS ALONG THE RTE WERE CALLING FOR OVCST CLOUDS WITH TEMPS AROUND FREEZING THROUGHOUT THE FORECAST PERIOD. THERE SEEMS TO BE SOME MISUNDERSTANDING FOR WHAT CONSTITUTES KNOWN OR FORECAST ICING AT THE DISPATCH LEVEL. THE LAST ISSUE IS THAT; AS A FLT CREW; WE WERE HEAVILY TASK LOADED WITH THIS PROB AND; THEREFORE; TOOK A WHILE WITH OUR NORMAL DUTIES BEFORE WE FOUND THEPROB WITH FLYING INTO ICING. IF MAINT CTL HAD BEEN MORE PRO-ACTIVE AND HAD TOLD US OVER THE RADIO WHAT THE STIPULATIONS WERE FOR CONTINUED FLT OR FOR THE OPERATIONALLY LIMITING MEL RIGHT AT THE BEGINNING; WE COULD HAVE SAVED A LOT OF FUEL AND TIME BY RETURNING TO CMH IMMEDIATELY OR FLYING INTO A FIELD THAT HAD MORE FAVORABLE NON-ICING CONDITIONS. IN THE END; WE SWAPPED ACFT IN CMH AND WERE ABLE TO ACCOMMODATE ALL OUR ORIGINAL PAX AND A FEW THAT HAD BEEN XFERRED FROM ANOTHER FLT. WE ARRIVED IN BOS WITHOUT FURTHER INCIDENT.